package koal.rsa_sign;

import java.security.Provider;
import java.security.Security;
import java.security.cert.X509Certificate;
import java.util.Collection;
import java.util.Iterator;
import org.bouncycastle.cert.X509CertificateHolder;
import org.bouncycastle.cert.jcajce.JcaX509CertificateConverter;
import org.bouncycastle.cms.CMSProcessable;
import org.bouncycastle.cms.CMSProcessableByteArray;
import org.bouncycastle.cms.CMSSignedData;
import org.bouncycastle.cms.SignerInformation;
import org.bouncycastle.cms.SignerInformationStore;
import org.bouncycastle.cms.jcajce.JcaSimpleSignerInfoVerifierBuilder;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.util.Store;
import org.bouncycastle.util.encoders.Base64;

public class VerifySignature {

	static final String DIGEST_SHA1 = "SHA1withRSA";
	static final String BC_PROVIDER = "BC";

	public static void main(String[] args) throws Exception {

		String envelopedData = "MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIAwggLQMIIC"
				+ "OQIEQ479uzANBgkqhkiG9w0BAQUFADCBrjEmMCQGCSqGSIb3DQEJARYXcm9zZXR0YW5ldEBtZW5k"
				+ "ZWxzb24uZGUxCzAJBgNVBAYTAkRFMQ8wDQYDVQQIEwZCZXJsaW4xDzANBgNVBAcTBkJlcmxpbjEi"
				+ "MCAGA1UEChMZbWVuZGVsc29uLWUtY29tbWVyY2UgR21iSDEiMCAGA1UECxMZbWVuZGVsc29uLWUt"
				+ "Y29tbWVyY2UgR21iSDENMAsGA1UEAxMEbWVuZDAeFw0wNTEyMDExMzQyMTlaFw0xOTA4MTAxMzQy"
				+ "MTlaMIGuMSYwJAYJKoZIhvcNAQkBFhdyb3NldHRhbmV0QG1lbmRlbHNvbi5kZTELMAkGA1UEBhMC"
				+ "REUxDzANBgNVBAgTBkJlcmxpbjEPMA0GA1UEBxMGQmVybGluMSIwIAYDVQQKExltZW5kZWxzb24t"
				+ "ZS1jb21tZXJjZSBHbWJIMSIwIAYDVQQLExltZW5kZWxzb24tZS1jb21tZXJjZSBHbWJIMQ0wCwYD"
				+ "VQQDEwRtZW5kMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC+X1g6JvbdwJI6mQMNT41GcycH"
				+ "UbwCFWKJ4qHDaHffz3n4h+uQJJoQvc8yLTCfnl109GB0yL2Y5YQtTohOS9IwyyMWBhh77WJtCN8r"
				+ "dOfD2DW17877te+NlpugRvg6eOH6np9Vn3RZODVxxTyyJ8pI8VMnn13YeyMMw7VVaEO5hQIDAQAB"
				+ "MA0GCSqGSIb3DQEBBQUAA4GBALwOIc/rWMAANdEh/GgO/DSkVMwxM5UBr3TkYbLU/5jg0Lwj3Y++"
				+ "KhumYSrxnYewSLqK+JXA4Os9NJ+b3eZRZnnYQ9eKeUZgdE/QP9XE04y8WL6ZHLB4sDnmsgVaTU+p"
				+ "0lFyH0Te9NyPBG0J88109CXKdXCTSN5gq0S1CfYn0staAAAxggG9MIIBuQIBATCBtzCBrjEmMCQG"
				+ "CSqGSIb3DQEJARYXcm9zZXR0YW5ldEBtZW5kZWxzb24uZGUxCzAJBgNVBAYTAkRFMQ8wDQYDVQQI"
				+ "EwZCZXJsaW4xDzANBgNVBAcTBkJlcmxpbjEiMCAGA1UEChMZbWVuZGVsc29uLWUtY29tbWVyY2Ug"
				+ "R21iSDEiMCAGA1UECxMZbWVuZGVsc29uLWUtY29tbWVyY2UgR21iSDENMAsGA1UEAxMEbWVuZAIE"
				+ "Q479uzAJBgUrDgMCGgUAoF0wGAYJKoZIhvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUx"
				+ "DxcNMTMwNTIxMDE1MDUzWjAjBgkqhkiG9w0BCQQxFgQU8mE6gw6iudxLUc9379lWK0lUSWcwDQYJ"
				+ "KoZIhvcNAQEBBQAEgYB5mVhqJu1iX9nUqfqk7hTYJb1lR/hQiCaxruEuInkuVTglYuyzivZjAR54"
				+ "zx7Cfm5lkcRyyxQ35ztqoq/V5JzBa+dYkisKcHGptJX3CbmmDIa1s65mEye4eLS4MTBvXCNCUTb9"
				+ "STYSWvr4VPenN80mbpqSS6JpVxjM0gF3QTAhHwAAAAAAAA==";
		String Sig_Bytes = "YduK22AlMLSXV3ajX5r/pX5OQ0xjj58uhGT9I9MvOrz912xNHo+9OiOKeMOD+Ys2/LUW3XaN6T+/"
				+ "tuRM5bi4RK7yjaqaJCZWtr/O4I968BQGgt0cyNvK8u0Jagbr9MYk6G7nnejbRXYHyAOaunqD05lW"
				+ "U/+g92i18dl0OMc50m4=";

		Provider provider = new BouncyCastleProvider();
		Security.addProvider(provider);
		CMSSignedData signedData = new CMSSignedData(Base64.decode(envelopedData.getBytes()));

		CMSProcessable cmsProcesableContent = new CMSProcessableByteArray(Base64.decode(Sig_Bytes.getBytes()));
		signedData = new CMSSignedData(cmsProcesableContent, Base64.decode(envelopedData.getBytes()));
		// Verify signature
		Store store = signedData.getCertificates();
		SignerInformationStore signers = signedData.getSignerInfos();
		Collection c = signers.getSigners();
		Iterator it = c.iterator();
		while (it.hasNext()) {
			SignerInformation signer = (SignerInformation) it.next();
			Collection certCollection = store.getMatches(signer.getSID());
			Iterator certIt = certCollection.iterator();
			X509CertificateHolder certHolder = (X509CertificateHolder) certIt.next();
			X509Certificate certFromSignedData = new JcaX509CertificateConverter().setProvider(BC_PROVIDER)
					.getCertificate(certHolder);
			if (signer.verify(
					new JcaSimpleSignerInfoVerifierBuilder().setProvider(BC_PROVIDER).build(certFromSignedData))) {
				System.out.println("Signature verified");
			} else {
				System.out.println("Signature verification failed");
			}
		}
	}

}
